1. Field of the Invention
The present invention relates to a pattern forming method, an actinic-ray-sensitive or a radiation-sensitive resin composition and a resist film. In more detail, the present invention relates to a pattern forming method, an actinic-ray-sensitive or a radiation-sensitive resin composition, and a resist film suitably used for a manufacturing process of semiconductor such as an IC, a manufacturing process of circuit board such as a liquid crystal and thermal head, and also a lithography process of photofabrication in addition to these. In particular, the present invention relates to a pattern forming method, an actinic-ray-sensitive or a radiation-sensitive resin composition, and a resist film suitably used for exposures in an ArF an exposure apparatus, an ArF liquid immersion type projection exposure apparatus, and an EUV exposure apparatus of which a light source is far ultraviolet light with a wavelength of 300 nm or less.
2. Description of the Related Art
After resists for a KrF excimer laser (248 nm) were developed, an image forming method using chemical amplification has been used in order to compensate for sensitivity decrease due to light absorption. For example, in a positive type image forming method of chemical amplification, an acid generator included in an exposed area generates acid by being decomposed by light irradiation. Then, in a post exposure bake (PEB) process after exposure and the like, an alkali-insoluble group included in a light sensitive composition is changed to an alkali-soluble group by a catalytic reaction of the acid generated. After that, for example, development is carried out using the alkali solution. As a result, the exposed area is removed and a desirable pattern is obtained.
In the method described above, a variety of alkaline developers have been proposed. For example, an aqueous alkaline developer such as an aqueous solution of 2.38% by mass TMAH (tetramethylammonium hydroxide) is generally used as the alkaline developer.
For microfabrication of semiconductor devices, shorter wavelength of exposure light source and higher numerical aperture of projection lens (high NA) have been progressed, and now, an exposure apparatus with an ArF excimer laser having a wavelength of 193 nm as light source is being developed. As a technology which further enhances resolution, a method in which liquid with a high refractive index (hereinafter, also referred to as “immersion liquid”) is filled between a projection lens and a sample (that is, an immersion method) has been proposed. An EUV lithography in which an exposure is carried out using ultraviolet light of shorter wavelength (13.5 nm) has also been proposed.
In addition, a variety of compounds have been developed for use as a photoacid generator, which is a major component of a chemical amplification type resist composition (see, for example, WO 2009/051088, WO 2011/093280, JP2009-25619A, JP2011-81045A, JP2011-79778A, and JP2010-100595A). In each patent document, photoacid generators having characteristic structures in the anion part are described.
However, practically, it is extremely difficult to find a suitable combination of resist composition, developer, rinsing solution and the like required to form a pattern of which performance is comprehensively satisfactory, and further improvements are required.
Recently, a negative-type pattern forming method using a developer including an organic solvent has been developed (see, for example, JP2010-164958A and JP1992-39665A (JP-H-04-39665A)). In JP2010-164958A, a pattern forming method having a step in which a resist composition containing a resin, which has a relatively high content of repeating unit having a group generating a polar group by being decomposed by an action of acid, is developed using a developer containing an organic solvent is disclosed. It is described that a micro pattern with satisfactory line width roughness (LWR), exposure latitude (EL), depth of focus (DOF) and the like, may be formed according to these methods.
In addition, in JP1992-39665A (JP-H-04-39665A), a patterning by an organic solvent (xylene) using a resist composition made of a copolymer of adamantyl methacrylate and t-butyl methacrylate is disclosed.
However, further improvements are required in the formation of a negative-type pattern by organic solvent development with regard to a suppression of pattern collapse and bridge defect generation after development, and an improvement of residual film ratio (suppression of a film reduction).